I'm relatively new to smoking so I'm still working on the basics. But.... they say mixing is great. And based on my experience of using apple and hickory separately, I think they'd be primo for mixing!

This evening I plan on just doing a slab of baby backs on the Performer and I'm going to try mixing some maple chips and cherry chips. Just yesterday I stocked up on chips at Menards; got one bag of each; apple, cherry, maple, mesquite, and hickory. The mesquite and hickory were on sale for $1.49 for a 2lb bag.

When I used to smoke a lot of fish, I used a blend of Alder and Hickory. I didn't care for the strong Hickory flavor and the Alder toned it down.
Now I use blends of Hickory, Oak and Maple on meats I smoke. Ratios depend on what sounds good that day.